Three Research Cores are proposed to facilitate interdisciplinary research into hearing and deafness at the Massachusetts Eye and Ear Infirmary (MEEI). The Research Center comprises 19 NIDCD-funded principal investigators, all affiliated with the Eaton-Peabody Laboratory (EPL). They include clinicians and basic scientists, with academic ties to graduate programs and departments at Harvard Medical School and MIT. The Research Base covers a wide range of basic and applied research projects from peripheral mechanics to cortical processing, from in vitro systems to human patients, from animal models to neural nets. The EPL research group has a long history of fruitful collaboration based on sharing of equipment, resources and scientific expertise via a system of research cores supported by a sunsetting program project grant. The current proposal builds on the present core structure and personnel to maintain existing, and facilitate further, interdisciplinary research efforts into hearing and deafness. Each of the Cores will support highly experienced personnel to 1) staff, stock, maintain and upgrade existing shared research facilities; 2) train users and/or render expert technical services in these facilities; and 3) provide the necessary expertise to enhance research productivity and facilitate the fusion of different research approaches across the many disciplines represented in the Research Center. The three Cores and the major aims of each include 1) an Engineering Core to design, build and maintain data-acquisition systems, custom acoustical devices, stimulus generation systems, a distributed multi-platform system for computational infrastructure and the local area network to link it all together 2) a Surgery/Histology Core to maintain existing shared facilities and assist research teams in animal surgery and histological preparation for both light and electron microscopy; and 3) an Imaging Core to support the growing needs of Center investigators for digital image acquisition and analysis, including confocal microscopy, computer-aided anatomical reconstruction, automation of morphometry, 3-D reconstruction/rendering, and analysis of functional imaging data.